Field of the Invention
This invention relates generally to a system for supplying a liquid of a prescribed composition to an operation at which the liquid is applied and is thereafter returned to the source of the liquid for further application to the operation following the effecting of any adjustments to the composition of the liquid at the source required to provide at the source the liquid of the prescribed composition. In particular, the invention relates to systems for supplying such liquids from a plurality of sources to a plurality of operations.
Discussion of the Prior Art
A variety of operations, such as are carried out in industrial settings, for example, call for systems for supplying to the operations liquids that are applied at the operations. A system of this type can include equipment for and methods of preparing a liquid according to a prescribed composition, as may be required at the operation, and delivering the liquid to the operation as needed. After application at the operation, the liquid is returned to its source and thereafter reapplied at the operation. An example of such an operation is a metalworking operation. The metalworking operation can involve, for example: metal fabricating, such as stamping for example; machining, such as milling for example; and lapping, polishing or grinding. Metalworking liquids that are delivered to the interface between a work piece and a metalworking tool at these operations are important to the effective performance of the operations. The metalworking liquids can be variously referred to, for example, as coolants, lubricants or cutting liquids.
Various types of metalworking liquids can be used in such operations. For example, straight oils, soluble, or emulsifiable oils, semi-synthetic liquids or synthetic liquids can be employed. The metalworking liquids can perform a variety of functions. For example, the metalworking liquids can: cool the work piece and the metalworking tool to keep the metalworking tool temperature down to prevent premature wear and damage of the metalworking tool and to keep the work piece temperature down to prevent warping of the work piece or the establishment of inaccurate dimensions in the work piece; provide a good finish on the work piece; and wash away fines, chips and swarfs from the work piece and the metalworking tool. The metalworking liquids can include additives such as, for example, additives for maintaining pH stability, corrosion inhibitors and biocides.
In many instances, a metalworking liquid after having been applied at a metalworking operation, and thereafter removed from the metalworking operation to the source of the metalworking liquid, is subsequently reapplied at the metalworking operation. As these metalworking liquids perform their functions at the metalworking operations, they can become contaminated by waste oils, referred to as “tramp oils,” which can come, for example, from hydraulic liquids, way oils, lubricating oils, tapping oils and gear box oils at the metalworking machines used in the metalworking operations. In addition, the overall quality of the metalworking liquids can degrade in one fashion or another through use. Consequently, before these metalworking liquids can be reapplied at the metalworking operations, and in order to extend the useful life of the metalworking liquids, contaminants such as fines, chips, swarf and tramp oils are removed from the metalworking liquids on a continuous basis or by a batch process. The cleaning of the metalworking liquids can be carried out using, for example, filtration or separation techniques, and belt or disc skimmers. At the same time, the composition or make-up of the metalworking liquids following their application at the metalworking operations can require adjustment to their original prescribed compositions to correct for the degradation that has occurred or to alternate prescribed compositions. It is preferable that the metalworking liquid be returned to the metalworking operation only after the metalworking liquid has been cleaned and given a desired composition.
There is a need in the art to provide an efficient liquid supply system that can function in real time to continuously provide liquid of good quality and a desired composition to an operation at which the liquid is applied from a source of the liquid and after being applied is returned to the source for further application, i.e., recirculated, to the operation. The system should have the following attributes: the system should be capable of analyzing at a desired frequency the composition of the liquid as the liquid is continuously applied to the operation from the source of the liquid; based on the analysis that is made, the system should be able to determine the amounts of the constituents of the liquid that are to be added to the liquid at the source of the liquid to provide a liquid of the original prescribed composition or a desired modified prescribed composition; the system should be capable of adding to the liquid at the source of the liquid the amounts of liquid constituents of the liquids that have been determined must be added to provide at the source of the liquid a liquid of the prescribed composition; and the system should be capable of delivering the liquid of the prescribed composition to the operation. In one context, there is a need in the art to provide such an efficient system that can function in real time in connection with a metalworking operation in which a metalworking liquid is applied from a source of a metalworking liquid, such as sump for example, to a metal work piece and a metalworking tool and after which the spent metalworking liquid, the quality of which has typically degraded, is returned to the source of the metalworking liquid for further application to the metalworking operation. In particular, there is a need for such a system that can function with multiple metalworking operations and multiple metalworking machines.